1. Technical Field
The present invention relates to a pressure key used in a keyboard, especially a digital/analog integrated pressure key which is capable of being able to output a digital signal first, and then output an analog signal while maintaining the digital signal on.
2. Description of Related Art
FIG. 1 is a prior art
FIG. 1 is a two-pressure-key system disclosed in US2010/0148999 which is used in a keyboard for outputting a digital signal and an analog signal. It discloses an analog key 202 and a digital key 203. In operation, depressing the analog key cap 202 shall cause an analog signal output 220, and depressing digital key cap 203 shall cause a digital or on/off output 222. The analog key provides a variable output, and the digital key provides a momentary-on output. A plastic base 212 supports the key structure. A flexible PCB (printed circuit board) 210 is provided on top of the base 212. The PCB 210 includes circuit traces or connections that provide for electrical signals to be generated and communicated when keys are depressed. Circuit connection 236 is used to provide digital output 222, and circuit connection pads 230 and 231 are used to provide the analog output 220. The next layer is flexible insulator 208, such as a flexible PCB without circuit connections. The next layer is another flexible PCB206 that includes circuit traces or connections that work in conjunction with the connections on PCB 210 to provide for electrical signals to be generated and communicated when keys are depressed.
A relatively thin flexible layer 204 is provided above PCB 206. A flexible dome 215 is provided for analog key cap 202, and flexible dome 213 is provided for digital key cap 203. For the digital key, an actuator 214 is provided underneath the dome 213 that causes circuit trace 234 to be engaged with circuit trace 236 when the digital key cap 203 is depressed. When circuit trace 234 touches the circuit trace 236, a digital output 222 is provided. For the analog key, a conductive and flexible half-dome 216 is provided that flexes when depressed. The capacitance associated between circuit pad 231 and circuit pad 230 varies when analog key cap 202 is depressed. Essentially pad 231 and pad 230 are the two plates of a capacitor. The variable capacitance between these two plates is measured from signal trace 232 by sending this trace to capacitance reading circuitry.
The separate key system is not an easy controlling device for a game player. A favorable controlling device for outputting a digital signal and an analog signal device needs to be devised.